Traditional heart-rate meter heart rate bands and heart rate belts generally comprise a body made of plastic, on the surface of which there are two local electrodes to be placed against the chest. Electronics for transmitting a heart rate signal, typically to a wristop device, are built into the plastic body. Conductors from the electrodes to the electronics also run inside the body, which is generally attached against the chest with the aid of a flexible band.
Because plastic heart rate bands are relatively thick and can feel uncomfortable in use, heart rate belts and sensory utilizing textile materials in particular have been developed recently. One such is disclosed in WO publication 2005/032366. In the solution depicted in it, the electrodes and transmission conductors are surfaced with a conductive material directly in the textile material. The transmission conductors can afterwards be coated with an insulating material, so that only the electrodes remain in contact with the skin and the quality of the signal improves. However, the laminate then remains on the surface of the product at the conductors, so that the breathability of these locations is reduced and they may feel uncomfortable against the skin.
WO publication 2002/071935 (FI 110925) discloses a heart rate sensor, in which there are electrodes containing conductive fibres, at the ends of which there is a moisture-retaining layer to improve the electrical contact of the electrodes with the skin. This solution also has a problem with the placing of the signal transmission conductors relative to the fibre material, particularly with creating both reliable contacts with the electrodes for them and good electrical insulation.
WO publication 2003/082103 discloses a heart rate sensor, with electrodes made by moulding through a textile material. The electrical conductors can be added to the mould, in order to attach them securely to the electrode moulding. However, the electrical conductors remain loose of the surface of the fabric and liable to mechanical stresses acting on them. They can also be attached as part of the textile with the aid of thermo-compression, but then a powerful interference signal may connect to them from the skin through the fabric.
WO publication 2005/0043641 discloses a device intended to measure heart rate, which can be detachably attached to a flexible band, or piece of apparel, with the aid of hooks in it. Though it can be attached to many different pieces of apparel, it does not eliminate the problem of discomfort when using traditional heart rate bands.
Currently, there are heart rate monitor belts which people can wear underneath their clothing in order to monitor their heart rate. Such belts are typically designed such that a telemetric transmitter is detachably connected to a belt having two electrodes which are in contact with the user's skin in the chest region of the user's torso. The electrodes identify an electric ECG pulse caused by the heart and then the detachable telemetric transmitter transmits data indicative of the user's heart beat with the use of wireless magnetic near field communication or a radio signal to a remote receiver provided with a display. In many instances the remote receiver is provided in the form of a wrist watch, wrist top computer or other similar display carried by a user, typically on the user's wrist.
Since various acceleration and magnetic sensors can be integrated in small and lightweight devices, the telemetric data to be transferred may, instead of or in addition to the heart rate, comprise a plurality of measured variable data, such as working frequency, pedaling rate and pedaling frequency, travel speed, etc. The data to be transferred may additionally comprise data required for the identification of the user and/or the transmitter device.
U.S. application No. 11/808,391 filed Jun. 8, 2007 and published as US 2007/0285868 which is herein incorporated by reference in its entirety, for instance, discloses a heart rate monitor belt which comprises a plurality of electrodes and a detachable telemetric transmitter.
It is preferably to have a telemetric transmitter which is detachable from a heart rate monitor belt for several reasons. From a consumer point of view, a user is typically sweating while using a heart rate monitor belt and it is therefore advantageous to be able to separate the electronic telemetric transmitter from the belt so that the belt can be washed. From a manufacturing point of view, the process for manufacturing the belt is substantially different from that of manufacturing the transceiver and therefore it is beneficial to be able to manufacture the components separately. Additionally, it is beneficial for one telemetric transmitter to be interchangeable with a plurality of belts.
Though there are several alternative methods for detachably connecting a telemetric transmitter to a heart rate monitor belt, the industry has almost entirely adopted the use of a pair of standard garment snaps. These standard garment snaps typically are mounted on the material of a heart rate monitor belt and virtually their entire thickness of around 4 mm protrudes from the outer surface of the belt.
Due to the existing technology and methods for detachably connecting telemetric transmitters it has not been realistic to incorporate heart rate monitor electrodes in to typical garments. In fact, the primary road block to such incorporation has been the size and bulkiness of the standard garment snaps. No clothing manufacture, nor consumer, has wanted 4 mm protrusions from their garments such as tops, shirts and sports bras.
Therefore, the garment industry has incurred a long felt need for an improved method of detachably connecting a telemetric transmitter to an article of clothing which does not compromise the integrity and utility of the underlying garment. However, the telemetric transmitter manufacturing industry has already adopted certain standards which relate to the use of a pair of male studs on a telemetric transmitter to be detachably snapped in to a pair of snaps on a heart rate monitor belt. As such, it would not be economical to wholly redesign the male portions of telemetric transmitters and the method in which they connect to an object having the necessary electrodes for measuring a user's heart rate.
Thus, there exists a need for a snap which fulfils the requirements of the garment industry but which fits in at least partially with the existing standards of the telemetric transmitter manufacturing industry. However, several critical issues arise when attempting to merely minimize the existing standardized snap. The main issue is the integrity of the connection between the male stud and the snap. Any amount over movement of the male stud within the snap will create electrical noise which makes difficult to impossible to accurately measure parameters such as a user's heart beat. Additionally, as a user is typically involved in strenuous activity while utilizing the product, the connection needs to withstand, and support the telemetric transmitter during such activity. As the depth of the snap decreases, the forces required to insure a reliably stable connection significantly increase.
Further yet, users typically sweat while undergoing strenuous activity wearing the product. As a reliable electrical connection is necessary between the telemetric transmitter and the electrode on the user's skin, it is important to keep the connection moisture free to reduce the likelihood of any shorts. Similarly, the problem is compounded for users who wish to utilize a heart rate monitor under water, for example while swimming or diving.
Therefore, there exist numerous challenges in the art to the development of a means of detachably connecting a telemetric transmitter to a garment having electrodes for monitoring a user's heart beat which aims to satisfy user's need, the garment manufacturer's needs and the needs of telemetric transmitter manufactures.